STUDY OF QUICK START-UP STRATEGIES FOR AN ULTRA-COMPACT BIOFILM REACTOR (UCBR) TREATING DOMESTIC WASTEWATER

Abstract

An Ultra-Compact Biofilm Reactor (UCBR) is capable of treating domestic wastewater at a short HRT of less than 2 hours. However, the long start-up time needed for biofilm formation is a major drawback for its full-scale application. Hence, this study aims to develop seed organisms to enhance biofilm formation and to establish a quick start-up strategy for UCBR to treat domestic wastewater.

To achieve this objective, domestic wastewater treatment and growing biofilm on bare sand carriers in a 5.4-L UCBR were carried out. Return activated sludge from a local water reclamation plant was used to inoculate the bare sand.

Seed from the 5.4-L UCBR was successfully used to inoculate a 2-L UCBR. Start-up strategies were studied using different feed substrate conditions on the 2-L UCBR. There were 5 phases to the study. The 5 phases were (I) 100% DWW without pH control, (II) 100% DWW with pH control, (III) 25% SWW blended with 75% Domestic wastewater with pH control, (IV) 50% SWW blended with 50% DWW with pH control and (V) 100% SWW with pH control. In Phases I and II, pH control was shown to improve the nitrification efficiency. pH control was subsequently applied to Phases III to V.